Conventional refrigeration and air-conditioning systems include a compressor, a condenser, an expansion device, and an evaporator. Refrigerant is circulated through the system to produce cooling. Energy is provided to the system by the compressor which serves to create a source of high pressure gas refrigerant which is allowed to pass through the condenser. The refrigerant dissipates heat in the condenser and changes state to a high pressure liquid. The refrigerant then passes through the expansion device and into the evaporator where the refrigerant changes from a high pressure liquid to a low pressure liquid, and subsequently to a low pressure gas. The change of state removes heat from the area surrounding the evaporator. The refrigerant is then drawn from the evaporator back to the compressor in a low pressure gas form, where it is again compressed into high pressure gas for repetition of the cycle.
An accumulator is normally located between the evaporator and the compressor in the system. The accumulator ensures that only refrigerant in a gas or vapor stage passes into the compressor, as refrigerant from the outlet of the evaporator often includes both a liquid component and a vapor component. In some accumulators, the vapor component is collected in the upper region of the accumulator, while the liquid component, along with any lubricating oil, drains to the lower region of the accumulator. The vapor component of the refrigerant is removed from the upper region of the accumulator by a U-shaped return conduit. The return conduit typically includes a metering device (e.g., a bleed-through orifice) at the lower portion thereof which draws a small amount of oil and liquid refrigerant back into the return conduit for lubrication of the downstream components, for example, the compressor.
One drawback associated with some accumulators has been that under certain operating circumstances, such as during start-up, incoming refrigerant enters the accumulator at high velocities and if directed at the stored liquid refrigerant, can disrupt and splash the stored liquid refrigerant. Such splashing can cause uncontrolled return of the refrigerant through the return conduit to the compressor, which is undesirable in certain circumstances.
To prevent this, some accumulators include a baffle (or deflector) which is supported within the inlet stream of refrigerant. The baffle prevents the incoming refrigerant from impacting directly against the stored liquid refrigerant, and instead attempts to direct the incoming refrigerant into the stored liquid smoothly. The baffle also facilitates separating the gaseous refrigerant from the liquid refrigerant.
On particularly useful accumulator is illustrated in U.S. Pat. Nos. 5,076,071; 4,827,725; 4,651,540; and 4,627,247. These patents show a circular baffle disposed at the upper part of the accumulator housing. The incoming refrigerant is introduced into the housing axially through the upper end cap and redirected by the baffle tangentially to the inside walls of the housing. The baffle includes a central circular aperture with a shoulder portion which engages the outlet end of the return conduit. The baffle has an upper spiral or helical surface around the central opening which receives the incoming refrigerant, and directs the refrigerant in a spiralling downward path along the inside surface of the housing. The liquid flows downwardly to join the liquid stored in the lower portion of the housing, and liquid refrigerant is separated from the gaseous refrigerant by centrifugal force. The spiraling refrigerant smoothly enters the stored liquid without substantial splashing, and thus without causing uncontrolled return of the liquid refrigerant to the compressor. It is also believed that the spiral baffle in the accumulator facilitates separating gaseous refrigerant from liquid refrigerant.
While the above type of accumulator has received widespread acceptance in the marketplace, the baffle is supported against both the upper end of the return conduit and the inside surface of the upper end cap. The return conduit is itself supported at the lower end of the housing. The baffle must be closely fit (sealed) against the upper end cap and the return conduit to prevent leakage. This requires relatively tight control of the tolerances between the return conduit, baffle and upper end cap in order to manufacture and assemble the accumulator. Such tight control of the tolerances can increase the manufacturing steps, labor costs, and generally the over-all costs of the accumulator.
In addition, the baffle is sometimes brazed to the end cap to facilitate fluidly sealing the baffle to the end cap. This can also require extra manufacturing steps and increase the labor costs.
As such, it is believed there is a demand in the industry for a further improved accumulator which provides controlled introduction of the liquid refrigerant into the stored liquid, but which allows greater tolerance stack-ups between components, particularly between the baffle, upper end cap and return conduit, so as to reduce the manufacturing and assembly costs. It is also believed there is a demand in the industry for an accumulator with reduced assembly steps, such as the elimination of the brazing step between the baffle and the upper end cap, so as to also reduce manufacturing and assembly costs. In any case, it is believed that there is a continual demand for an efficient and low-cost accumulator which effectively separates gaseous refrigerant from liquid refrigerant.